A new species of Coespeletia (Asteraceae, Millerieae) from Venezuela

Abstract A new species of Coespeletia from the páramos of Mérida (Venezuela) is described here. This species, named Coespeletia palustris, is found in a few marshy areas of the páramo. It is closely related to C. moritziana, but differs from it in a smaller number of florets in the capitula, larger ray flowers with longer ligulae and longer linguiform appendages, smaller pollen grains, larger cypselae, ebracteate scapes, leaves and inflorescences with more whitish indumentum, larger leaf sheaths, and marshy habitat.


Introduction
Th e genus Coespeletia Cuatrec. (Espeletiinae: Asteraceae) was described based on its racemiform monochasial infl orescences, sometimes reduced to a monocephalous scape, with capitula semiglobose or patelliform, and ray fl owers usually not exceeding the involucres. Later palynological studies supported this genus as a clade. Most of the Espeletiinae species have the Aspilia -pollen type, but the pollen type of Coespeletia is unique, called the Coespeletia -type (Salgado-Labouriau 1982;Cuatrecasas 2013). Pollen grains of this type have a larger number of equatorial spines (≥16), the spines are much shorter (≤4 μm), and have smaller spine length/polar diameter ratios (<0.15) than the rest of the Espeletiinae (Cuatrecasas 2013). Th ese pollen characteristics may represent a particular adaptation to wind pollination at high-elevation habitats (Cuatrecasas 2013), where most of the species of Coespeletia are found (Diazgranados 2012).
Currently there are seven described species of Coespeletia : six endemic to the Andes of Venezuela ( C. albarregensis Cuatrec., C. elongata (A. C. Sm.) Cuatrec., C. moritziana (Sch. Bip. ex Wedd.) Cuatrec., C. spicata (Sch. Bip. ex Wedd.) Cuatrec., C. thyrsiformis (A. C. Sm.) Cuatrec. (including C. thyrsiformis f. marcana (Cuatrec.) Cuatrec.), and C. timotensis (Cuatrec.) Cuatrec.), and one species recently discovered in northern Co- dos 2012). However, the latter species is under re-evaluation by the fi rst author. Th e Venezuelan species grow in the páramos of Sierra Nevada de Mérida, Sierra Nevada de Santo Domingo and Sierra del Norte in the state of Mérida, and in the Páramos de la Negra, del Batallón and del Zumbador in the state of Táchira (Diazgranados 2012;Cuatrecasas 2013). Most of the species are restricted to very high elevations, in a range between 3800-4800 m (Diazgranados 2012). Only one species can grow below 3000 m, six species can be found at 3800 m, and fi ve species are adapted to superpáramos at elevations above 4000 m. Th e highest elevation ever reported for any Espeletiinae specimen is 4780 m, for C. timotensis (coll. L.Ruiz-Terán 851 ). However, according to Cuatrecasas (2013), C. moritziana can grow above 4800 m, on rocky crests emerging from glacial blocks.
Even after decades of studies and collections in the páramos, numerous localities remain unstudied, and there are still several taxonomic problems and interesting challenges within the Espeletiinae (Diazgranados 2012). Th e new species described in this paper is called "palustris" because of the marshy habitat in which it grows. Highelevation marshes and wetlands are among the ecosystems which are most impacted by climate change (Rabatel et al. 2013, Vuille 2013. Th erefore this species may be at a certain risk of extinction as well.

Methods
Material of the new species was collected in the fi eld in 2011. Two expeditions were organized to the native habitat, and collections were preserved and distributed to the herbaria MER and VEN. Photomicrographs were taken by the fi rst author at the Scanning Electron Microscopy Laboratory of the National Museum of Natural History, in Washington DC. In addition, numerous collections already present in several herbaria were studied (see 'Specimens examined' section below, with specimens listed by geographic location, including specimens for C. moritziana and C. palustris ). Illustrations were done by Lauren Merchant, from Saint Louis University. Diagnosis. Related to Coespeletia moritziana but diff ers in indumentum primarily whitish, larger leaf sheaths, proximal portion of young leaves white, thicker scapes, which are ebracteate, larger phyllaries with pubescence unkempt, capitula with fewer fl owers, which are much larger, and smaller pollen grains.
Pollen yellow when fresh, tricolporate, 22.1-23.7 μm in equatorial diameter (not including spines), 25-26 μm in polar diameter; spines 110-116 total, equatorial spines 18, 2.3-3.2 μm long, slightly curved. Distribution (Fig. 4). Endemic to Venezuela. Th is species has been found in a few marshy areas of the Páramo de Santo Domingo (e.g. around the Laguna de los Patos) and the Sierra de la Culata, always in small areas of less than 0.5 km 2 .  Etymology. Th e name "palustris" is given because of the boggy habitat in which this species is found.
Conservation status. Th is species may be at a certain risk of extinction, since it is found in a very particular habitat, sensitive to climate change.

Discussion
Th is species is closely related to Coespeletia moritziana . However, the habitat of C. moritziana is a dry rocky crest of superpáramo, while C. palustris grows in swampy grassy areas. As recognized by Cuatrecasas (2013), C. moritziana is highly polymorphic, with two main "forms": the fi rst, which includes the type collection, with thin scapes often with sparse sterile bracts; and the second, with much thicker scapes, naked, larger capitula, and longer ray corollas. Here we separate the second "form" observed by Cuatrecasas as the new species C. palustris , which grows in marshy areas, in contrast with the typical C. moritziana , adapted to rocky crests of higher elevations.
Hybridization is quite common between Espeletiinae species (Diazgranados 2012). For instance, there are three hybrids reported for C. moritziana : Espeletia × aurantia Aristeg. ( C. moritziana × Espeletia schultzii ); C. moritziana × C. timotensis ; and E. schultzii × C. moritziana (Diazgranados 2012). However, the populations of C. palustris are morphologically homogeneous, and rather diff erent from the populations of C. moritziana seen in the rocky and colder superpáramos. Despite the high polymorphism of C. moritziana , there are several stable morphological diff erences between C. moritziana and C. palustris . Some of those diff erences seem to correspond to adaptation to their distinct habitats. For instance, an increase in the size of capitula and the number of fl orets seems to be an adaptation to the cryothermal zone (in C. moritziana ), while the thicker leaves with longer sheaths can be correlated with marshy habitats (in C. palustris ). Still, the polymorphic C. moritziana ' complex' will require additional taxonomical work in the near future.